WBR0391
| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Biostatistics/Epidemiology |
| Sub Category | SubCategory::Renal |
| Prompt | [[Prompt::A case-control study is investigating the association between the chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) over 1 year duration and impaired renal function. 2000 men and women over the age of 50 are surveyed, and the results of the study have been categorized in the following table. Which of the following numbers represents the odds ratio (OR) for renal impairment among patients with a history of chronic NSAID use, versus those without a history of chronic NSAID use?
|
| Answer A | AnswerA::0.041 |
| Answer A Explanation | [[AnswerAExp::0.041 represents the attributable risk, calculated using the following equation:
Attributable Risk = (a/[a+b]) – (c/[c+d])]] |
| Answer B | AnswerB::0.500 |
| Answer B Explanation | AnswerBExp::0.500 does not correspond to any relevant value. |
| Answer C | AnswerC::1.066 |
| Answer C Explanation | [[AnswerCExp::1.066 represents the relative risk (RR), often used in cohort studies. RR is calculated using the following equation:
RR = (a/[a+b]) / (c/[c+d])]] |
| Answer D | AnswerD::1.200 |
| Answer D Explanation | AnswerDExp::1.200 correctly represents the OR |
| Answer E | AnswerE::1.500 |
| Answer E Explanation | AnswerEExp::1.500 does not represent any relevant value. |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::
The odds ratio (OR) in this scenario is calculated using the equation:
OR = ad/bc = (800 x 300)/(400 x 500) = 240000/200000 = 1.2 |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Odds ratio, WBRKeyword::OR, WBRKeyword::Case-control, WBRKeyword::Equation, WBRKeyword::NSAID, WBRKeyword::Renal impairment |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
